Redaction refers to the removal of content from a document, such as by deleting or obscuring the content. Conventionally, redaction occurs when a person is to review a completed document, but is not entitled to review one or more portions of the document. The typical approach to performing such redaction is to make a copy of the document and, in the copy, remove the content that the reviewer is not entitled to review, such as by deleting it, overwriting it, etc.
For example, during the discovery phase of a lawsuit, the plaintiff may request from the defendant a copy of a particular sent email message. The defendant determines that the plaintiff is not entitled to receive a certain paragraph of the email message, based upon the attorney-client privilege doctrine. Accordingly, the defendant makes a paper or electronic image of the email message, deletes or overwrites the paragraph in question, and provides this modified image to the plaintiff in response to the request.